RTNET

RTnet is an Open Soure hard real-time network protocol stack for Xenomai and RTAI (real-time Linux extensions). It makes use of standard Ethernet hardware and supports several popular NIC chip sets, including Gigabit Ethernet. Moreover, Ethernet-over-1394 support is available based on the RT-FireWire protocol stack... RTnet implements UDP/IP, TCP/IP (basic features), ICMP and ARP in a deterministic way. It provides a POSIX socket API to real-time user space processes and kernel modules... To avoid unpredictable collisions and congestions on Ethernet, an additional protocol layer called RTmac controls the media access. A dedicated Ethernet segment is required to guarantee bounded transmission delays, but RTnet also includes a mechanism to tunnel non real-time traffic like TCP/IP over RTmac, thus allowing a "single-cable" solution for connecting control systems.